Known in the art is an electrosurgical instrument for dissecting various tissues, comprising an active electrode, i.e., a double-edged disk knife to which a diathermic current is fed, and a passive electrode. The knife blade is provided with an adjoining scraper (cf. USSR Inventor's Certificate No. 624,617 published 1978).
During surgery the disk knife receives rotation and is fed with an electric current. The tissue operated upon is incised by virtue of motion performed by the instrument. The coagulate formed on the knife blade is removed by the scraper.
The aforedescribed instrument operates on the bipolar monoactive cutting principle, which involves a passive plate electrode connected to a patient's body a certain distance apart from the knife, i.e., an active electrode. It is due to r.f. current dispersion and useless heating of the tissues located between the active electrode and the passive one that surgery on the internal organs becomes uncontrolled and proceeds unstably. This is turn makes the instrument inapplicable for surgical interference on vitally important organs, e.g., for dissecting the sternum, the spine, the hipbone, and the like. Moreover, the device in question is unsuitable for surgery on the aforementioned osseocartilaginous tissues also due to the fact that these tissues features increased mechanical strength so that even a ground-sharp disk-shaped electrosurgical knife fails to destruct such tissues, since even an inconsiderable "biting" of the knife into the tissue results in its "jamming" therein.
Another electrosurgical instrument is known to comprise a cutting portion which incorporates an active electrode in the form of a disk cutter, and a power actuator to impart rotation to said cutter, a passive electrode, and current leads to feed a diathermic current to the active electrode (cf. USSR Inventor's Certificate No. 194,982 published 1967).
The instrument described above is suitable for surgery on hard osseocartilaginous tissues but cannot also be applied in the areas where vitally important organs are located, since this instrument, like the instrument described previously operates on the bipolar monoactive cutting principle.